ABC transporter

ATP-binding cassette transporters (ABC-transporter) are members of a superfamily which is one of the largest, and most ancient families with representatives in all extant phyla from prokaryotes to humans. . These are transmembrane proteins  that function in the transport of a wide variety of substrates across extra- and intracellular membranes, including metabolic products, lipids and sterols, and drugs. Proteins are classified as ABC transporters based on the sequence and organization of their ATP-binding domain(s), also known as nucleotide-binding folds (NBFs). ABC transporters are involved in tumour resistance, cystic fibrosis, bacterial multidrug resistance and a range of other inherited human diseases.
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